Slide fastener with continuous coupling element



July 22, 1969 H. HEIMBERGER SLIDE FASTENER WITH CONTINUOUS COUPLINGELEMENT Filed Oct. 16, 1967 3 Sheets-Sheet 1 FUEL GAS

. HELMUT HEIMBERGER INVHN'I'OR.

FIG .3

ATTORNEY July 22,1969 H. HEIMBERGER 3,456,306

SLIDE FASTENER WITH CONTINUOUS COUPLING ELEMENT Filed Oct. 16, 1967 -3Sheets-Sheet 2 F l G 8 2 l I 49b Maggi 53 46 HELMUT HEIMBERGER rtINVIJ'N'I'OR.

+5; I 46 BY {Karl 5R1) July 22, 1969 H. HEIMBERGER 3 Sheets-Shea Filed001,. 16, 1967 HELMUT HEIMBERGER {Ka iRass United States Patent3,456,306 SLIDE FASTENER WITH CONTINUOUS COUPLING ELEMENT HelmutHeimberger, Essen, Germany, assignor t0 Opu- Holding AG., Glarus,Switzerland, a corporation of Switzerland Filed Oct. 16, 1967, Ser. No.675,697 Claims priority, application Germany, Oct. 15, 1966,

Int. Cl. A44b 19/24 US. Cl. 24205.16 8 Claims ABSTRACT OF THE DISCLOSUREA slide-fastener structure wherein a thermoplastic helicoidal ormeandering coupling element is attached to a stringer tape with the aidof a fillet cord flanking the coupling element and/or a core cordextending through the coupling element and with thermoplastic threads(e.g. in a chain stitch) extending along the coupling element andthermally fused to bond a plurality of loops together, to bond the loopsto the coupling element and/ or to bond the loops to the cords.

My present invention relates to improved slide-fastener structures and,more particularly, to a slide-fastener structure wherein a pair ofstringers, support tapes or bands are formed along their confrontingedges with matingly interengageable continuous coupling elements havingcomplementarily spaced heads which interengage upon movement of a slideralong these coupling elements; more particularly, this invention relatesto slidefastener assemblies using so-called meandering or helicoidalcoupling elements.

It has been found that continuous coupling elements of the meandering orhelicoidal type permit improved, snagfree, washable, drycleanable andpressable fasteners to be produced without difliculties which havehitherto been encountered with coupling elements consisting ofspaced-apart members individually fastened to an edge of a stringertape. The continuous coupling elements are generally formed ofmolecularly oriented filamentary synthetic resin material of athermosetting or thermoplastic type in which the heads of the couplingelements are formed by thermal deformation with a predetermined spacingalong the continuous filament. The term helicoida is used herein torefer to coupling elements in which the filament, usually a nylon-typepolyamide, is coiled in a multiplicity of generally similar turns, suchcoupling elements being usually formed on a mandrel and being thermallydeformed by pressing devices or the like after having been wound on thismandrel. The crosssection of the elongated coupling element may beeliptical, circular or any oval configuration and the turns may includemutually parallel and coplanar shanks connected by the coupling head,with the shanks of each head being connected with the adjacent shanks bybight portions bridging the turns. In systems of this type, the headsare provided with lateral protuberances which engage below thecorresponding protuberances of the mating heads and interfit with theturns of the opposing coupling element.

Meandering coupling elements can be described as continuous elements offilamentary thermoplastic or other synthetic resin (usually nylon-typepolyamides), of the molecularly oriented kind, which have been deformedinto a multiplicity of similar undulations which may be disposed on oneside of the stringer tape, may pass alternately back and forth from oneside of the tape to the other, or may simultaneously bridge the oppositesurfaces of the stringer. Again, the undulations usually have "ice bightportions which connect the heads and are secured to the stringer tape.Typical helicoidal slide fasteners are described in US. Patents No.3,267,514 and 3,243,489, as well as in my commonly assigned copendingapplication Ser. No. 544,487. Meandering coupling elements areillustrated and described in Patent No. 3,255,504.

Slide fasteners using meandering or helicoidal elements have beenproposed in a number of configurations and, indeed, it has beensuggested to cement coupling elements to the respective stringer tapes,to attach the coupling elements to stringerfoils by thermal welding, toenclose the coupling elements in woven sleeves of the stringer tapes andto sitch them to the latter. In the systems involving stitching of thecoupling element to a stringer tape, two approaches may be described,namely, the stitching technique wherein the individual turns orundulations of the coupling element are secured to a fabric or otherstringer tape by thread loops applied by a sewing machine, or thetechnique whereby a cord, core of other filler body extends along thecoupling element and there- Within for assisting in joining the couplingelement to the stringer tape. It has been suggested, moreover, to assignto the threads and filler cord functions beyond that of securing thecoupling element to the stringer tape. In one arrangement, for example,the means for securing the coupling element to the stringersimultaneously acts as protection for the bight portion of the couplingelement which otherwise might be subjected to wear from the slider ordevices for treating the fabric or the like. Conventional techniques ofthis character have not been fully satisfactory because of breakage ofthe stretches and/or core, because of the high frictional obstructionsto the slider introduced by such fastening means, the variability in thecharacter of the fastening device with washing and the like.

It is, therefore, the principal object of the present invention toprovide an improved slide-fastener assembly in which continuous couplingelements are attached to the stringer tapes by stitching.

Another object of my invention is to provide a slide fastener assemblyin which the means for aflixing the coupling element to the stringertape of each slide fastener half is capable of withstanding the stressesto which it is subjected to a greater extent than heretofore.

I have now found that it is possible to attach coupling elements of athermoplastic material to a fabric or foil stringer tape with threadsextending along the coupling element and interweaved with the couplingelement and/ or stringer tape or stitched thereto (eg as chain stitches)wherein the threads are composed of thermoplastic synthetic resin (e.g.of polyamide or polyester) which threads are thermally fused informfitting relationship to increase the ability of the attaching meansto with stand stress. When the terms thermal fusion and formfittingrelationship or expressions of similar import are used generallyhereinafter, they are to be understood to refer to systems in which theattaching threads are in surface contact with one another, with acontinuous cord or filler bead of thermoplastic material running throughor along the coupling elements in a conventional manner and composed ofa thermally Weldable synthetic resin according to the presentimprovement, and/or with the helicoidal or meandering coupling elementswhich are composed of continuous filamentary thermoplastic material; thethreads are bonded along the surface in such contact with one another,to the slider-guide head or fillet, to the core running through thecoupling element and/or to the coupling element itself in the region inwhich these threads engage the shanks. Furthermore, at the locations inwhich thermal welding is to take place, the expression formfitting isintended to include the concept of integrating the material of thethread with the material of the body to which the thread is thermallybonded (i.e. another thread of the stitching, another convolution, loopor stretch of the same thread, the bead or fillet, the core and/or thecoupling element), the integration forming substantially a mono lithicstructure at the thermal weld of the type characterizable as a flowingtogether of the thermally welded materials, an interditfusion orinterpenetration thereof and the like. All of these conditions areintended when the expression thermal welding is used hereinafter inconjunction with expressions relating to integration of the threadmaterials with the body to which they are bonded.

The assembly produced by, for example, thermally welding the threadsconstituting the stitching to one another along the length of thecoupling element to form a nonseparable fastening means capable ofwithstanding high stress and even forming a substantially continuousmember for guiding the slider, or the structure resulting from bondingthe thermoplastic threads to a fillet disposed alongside the couplingelement and stitched by the threads to the coupling element and thestringer tape, or the thermal welding of the threads of the stitching toone another, to the core passing through a helicoidal coupling elementor to the coupling element itself, has the significant advantage thatthread loops formed by loosening of the stitches or the woven fasteningthreads can be formed with use of the slide fastener and interfere withits movement along the coupling elements. Moreover, by avoiding suchloops, it is possible to prevent localized separation of the couplingelement from the stringer tape and/or dislocation of the couplingelement in such manner as to prevent movement of the slider therealong.Another surprising advantage is the increase in the transverse strengthof the slide fastener which can resist forces tending to separate theslide-fastener halves in the plane thereof to a greater extent thancoupling elements attached with normal stitching techniques. When, forexample, standard methods of measuring the transverse strength of aslide fastener, e.g. in terms of the force necessary to pull apart theclosed slide fastener per unit length in a direction transverse thereto,are used, it is found that there is a minimum increase of with thepresent improvement. In addition, the resistance of the slide fastenerto washing and dry-cleaning stresses is increased. The thermal weldingof the loops of the fasten ing stitches on or adjacent the couplingelements, which are composed of thermally fusible synthetic resin, canbe carried out in various ways in accordance with the instant invention.For example, when the coupling element is provided with a core orfillet, a heating device may be used to fuse the stitches whichcomprises a number of relatively small localized heating elements spacedapart in accordance with the distribution of the threads and the weldswhich engages the slide-fastener half as it is displaced afterstitching. A relatively simple technique involves the use of a radialheating device or a dielectric heater which fuses the free loops of thethread and forms from them thickenings or bulges, thereby shrinking thethread loops about the fillet or coupling element and produces a ridgealong which the slider can ride. The threads are integrated with anotherand thermally fused to the coupling elements or core as may be desired.General heating techniques may be used, however, since the thickness ofthe threads is substantially less than that of the attaching cords orcoupling elements so that the thermoplastic threads flow before thecoupling elements and attaching cords have been heated sufiiciently. Theportions of the threads within the cords remain unaffected by the heatwhich cannot damage the coupling elements. When the coupling elementsare composed of metal, inductive heating may be used to cause fusion andflowing of the threads at the locations at which they contact the metalelement. Gas-flame heating may also be employed.

The above and other objects, features and advantages of the presentinvention will become more readily apparent from the followingdescription, reference being made to the accompanying drawing in which:

FIG. 1 is a perspective view of a slide fastener embodying the presentinvention;

FIG. 2 is a cross-scectional view along the line II-II of FIG. 1 showingthe means for heating the threads in diagrammatic form and drawn to anenlarged scale;

FIG. 3 is a cross-sectional view similar to FIG. 2, illustrating anotherembodiment;

FIG. 4 is a cross-sectional view taken along the line IVIV of FIG. 1;

FIG. 5 is a plan view drawn to an enlarged scale and with parts removedshowing the relationship between the chain-stitch threads and thecoupling elements;

FIG. 6 is a view similar to FIG. 5 showing the relationship of thecoupling elements and attaching threads after thermal bonding;

FIG. 7 is a cross-sectional view similar to FIG. 4 illustrating anotheraspect of this invention; and

FIG. 8 is a view similar to FIG. 6 of another modificatron.

In FIG. 1 of the drawing, I show in diagrammatic form a slide fastener10 which comprises a pair of slidefastener halves 10a and 10b eachhaving a respective stringer tape 2 of fabric and provided with arespective coupling element of the meandering or helicoidal typerepresented in 1. The coupling elements may be composed of molecularlyoriented synthetic resin and are attached to the stringer tapes 2 asdescribed, for example, in connection with FIGS. 2 and 4-6. Flanking thecoupling elements 1, which may have the configuration illustrated in anyof the aforementioned patents or application, are a pair of fillet cords4 which protect the outer edges of the coupling elements and guide aconventional slider (not shown) therealong. While the present drawingillustrates stitching for retaining the coupling elements 1 on thestringer tapes 2, it will be understood that the present invention alsoapplies to systems in which the coupling elements 1 are woven into thefabric tapes, i.e. wherein the fabric tapes retain the coupling elementsvia threads from which these tapes are woven. The interweaving offlexible coupling elements of the character described into the fabrictapes is conventional in the art and need not be described in greaterdetail hereinafter except to note that the thermal fusion of thethermoplastic threads improves the anchorage of coupling elements towoven stringer tapes in which they are held by the interwoven threads.As shown in FIG. 2, however, the coupling elements 1 are retained on thestringer tapes 2 by stitching 3 through the cords 4 flanking thesecoupling elements which are here shown to be in their interengagedcondition. In this embodiment, the threads 3 of the stitching along theleft-hand slider half are thermally melted down and welded together toform thickenings 5a by a gas flame 11 from a torch 12 at the localitiesat which such thickenings are desired. In the system at the right-handside of this slide fastener, the stitching threads 3 are thermally fusedtogether and melted down by an infrared heater represented at 13 to formthe thickenings or condensed portions 5b along the upper surface of therespective fillet cord 4. The fillet cords 5 are here shown to be ofthermally fusible thermoplastic material which merge with the threads 3at the thickenings 5a or 5b and are integrated therewith. The stitching3 may be a doublechain stitch, vamping stitch or the like having one ormore loops bonded together by thermal welding as indicated previously.When a number of stitches are provided, it may be desirable to make useof nonthermally fusible threads for some of these loops and thermallyfusible threads for others. For example, the thread loops of thread 3ain FIGS. 4-6 may be composed of cotton while the thermally condensed andfused thread loops are composed of the thermoplastic material (e.g.polyamide or polyester resin).

In the system of FIG. 3, the stitches 23 pass through cores 24 Withinthe helicoidal coupling elements 21 on the stringer tapes 22. In thiscase, the thermal weldin of the stitches 23 at 25 to fuse them togetherand form thickenings or condensed portions thereon, also thermally bondsthe threads to the thermoplastic coupling elements 21 at the integratedinterfaces 28. It has been found that it is possible to eliminate thecores 24 and yet obtain a highly effective attachment of the couplingelements to the tape when the stitches 24 are fused to the couplingelements 21 at 25, as represented in FIG. 3. Since the stitches arefused together as well, a relatively continuous seam is provided alongthe full length of the coupling element, which is practicallyunravelable and can serve to guide the slider.

In FIGS. 46, the relationship between the different stitches can beseen. In this embodiment, the upper thread 3a and the lower thread 3battaching the couple elements 31 to the stringer tapes 32 are composedof cotton and thermoplastic material respectively, the stitch beingillustrated at the left-hand side of FIG. 4 while, at the righthand sideof this figure, the tightened stitches are shown securing the core 34within the helicoidal coupling elements. In accordance with conventionalpractice, the lower thread 3b forms the upper surfaces of the slidefastener and is heated (e.g. by the means illustrated in FIG. 7) tocondense the threads 3b and form from the loops thereof the lockingelements 6 which (compare FIGS. 5 and 6) are thermally bonded to thecoupling elements 31 at 38 and retain the nonthermally fusible threads3a in place. The locking elements 6 are here shown to be formed as eyesthrough which the threads 3a pass.

In the modification shown at FIG. 7, the thermally fusible threads 43::and 43b are both composed of thermoplastic material and form a chainstitch retaining the coupling element 41 on the tape 42, a thermoplasticcore 44 extending through the coupling element. Individual resistiveheaters 49 carried by a support 49a and spaced apart in accordance withthe spacing of the turns of the coupling element are brought intocontact with the threads 43a and 43b and heat them to the flowcondition, at which temperature the thermoplastic threads merge at 48with the coupling elements, at 48a with the synthetic-resin core 44 andwith each other at the thickened portion 48b. The support 49a isdisplaced by a drive 4% into and out of engagement with the slidefastener which is stepped in the direction of arrow 49c. In FIG. 8, Ishow an arrangement wherein synthetic-resin loops 46 are formed bythermal welding and condensation of one set of fastening threads and arebonded to the coupling elements at the upper surface thereof whileanchoring the lower threads 53 which may pass through the tape andaround the other shank of each coupling element to lock these threads inplace.

The invention described and illustrated is believed to admit of manymodifications within the ability of persons skilled in the art, all suchmodifications being considered within the spirit and scope of theappended claims.

I claim:

1. A slide-fastener structure comprising a stringer tape, acontinuous-filament coupling element having a multiplicity ofconvolutions of thermoplastic material extending along an edge of saidtape for mating interengagement with a complementary coupling elementupon movement of a slider therealong, and means including a thermallyfusible thread of a thermoplastic resin extending along said couplingelements for securing same to said tape and having a multiplicity ofthread loops passing between said convolutions and in contact therewith,said thread loops being thermally welded unitarily with saidconvolutions at regions of contact therewith to hold said convolutionsin place in the slide-fastener structure.

2. The slide-fastener structure defined in claim 1 wherein a pluralityof thread loops secure said convolutions to said tape and the threadloops along each convolution are thermally fused to one another.

3. The slide-fastener structure defined in claim 1, further comprising acontinuous cord of thermoplastic material extending along .said couplingelements and forming part of the means for securing same to said tape,said thread loops being thermally fused to said cord.

4. The slide-fastener structure defined in claim 3 wherein said cordflanks said coupling element.

5. The slide-fastener structure defined in claim 3 wherein said cordforms a core extending through said coupling element, said thread loopsconstituting a row of stitches securing said coupling element and saidcore to said tape.

6. The slide-fastener structure defined in claim 1 wherein the means forsecuring said coupling element to said tape includes thread ofrelatively nonfusible material interlinked with said thread ofthermopolastic resin and locked thereby in place upon thermal fusion ofthe latter thread.

7. A slide-fastener structure comprising a stringer tape, a continuouscoupling element having a multiplicity of convolutions extending alongan edge of said tape for mating interengagement with a complementarycoupling element upon movement of a slider therealong, and meansincluding a thermally fusible thread of a thermo plastic resin extendingalong said coupling elements for securing same to said tape, said threadbeing thermally fused in place in the slide-fastener structure, saidthread forming part of a double-chain stitch consisting of an upperthread and a lower thread, said lower thread being composed of thermallyfusible material and being thermally fused so as to form lockingelements in the form of annular eyelets retaining said upper thread.

8. A slide-fastener structure comprising a stringer tape, a continuouscoupling element having a multiplicity of convolutions extending alongan edge of said tape for mating interengagement with a complementarycoupling element upon movement of a slider therealong, and meansincluding a thermally fusible thread of a thermoplastic resin extendingalong said coupling elements for securing same to said tape and having amultiplicity of thread loops passing between said convolutions, saidthread loops including two loops assigned to each convolution thermallywelded unitarily together at regions of contact therewith to hold saidconvolutions.

References Cited UNITED STATES PATENTS 2,353,960 7/1944 King. 2,018,09910/ 1935 Sundback. 2,497,821 2/ 1950 Kohler. 2,901,803 9/1959 Porepp.2,994,631 8/ 1961 Ottinger. 3,147,529 9/ 1964 Wilcken. 3,333,305 8/ 1967Taylor.

FOREIGN PATENTS 514,934 7/ 1955 Canada.

1,130,263 5/1962 Germany.

BERNARD A. GELAK, Primary Examiner US. Cl. X.R.

